'I suspect I'd vote yes. I would vote yes because I'm seeing in this country too many lives being destroyed for non-violent offenses. We have a criminal justice system that lets CEOs on Wall Street walk away and yet we're giving jail sentences to young people who are smoking marijuana. We have to think through the War on Drugs, which has done an enormous amount of damage. We need to rethink our criminal justice system. We've got a lot of work to do in that area.'

Then Lopez directed a question to Clinton, who has said she's waiting to see how the legalization experiments in states like Colorado and Washington work before taking an official stand on the issue: "It's been more than a year since you said that. Are you ready to talk a position tonight."

Clinton fired back with an emphatic, "No," then added:

'We have the opportunity through states that are pursuing recreational marijuana to find out a lot more than we know today. I do support the use of medical marijuana. Even there I think we need to do a lot more research so we know exactly how we can help people for whom medical marijuana provides relief. But I believe completely that we've got to stop imprisoning people who use marijuana. Therefore, we need more states, cities and the federal government to begin to address this so that we don't have this terrible result that Sen. Sanders was talking about where we have a huge population in our prisons for non-violent low-level offenses that are primarily due to marijuana.'

The other candidates - Jim Webb, Lincoln Chafee and Martin O'Malley - were not asked a marijuana question.